The present invention relates to an anchor for boards for mounting an instrument or tool to a building material which does not provide screw retaining force such as a plasterboard or a sheet of plywood, or to a wall surface to the back of which hands cannot reach.
In a situation in which the building material itself is too thin and weak to mount a tool or instrument by directly tightening a screw, metal anchors are widely used. By tightening a screw, its leg portion spreads in all directions. Thus an operator can work on the front side only by forming a starting hole in the wall.
In such known anchors for boards, a screw is tightened from the operator""s side to spread the leg portion on the backside of the wall surface, thereby fixing the anchor to the board. After removing the screw, an article to be fastened is fixed by retightening the screw. After the article has been mounted, if a load is applied to the article, the leg portion of the anchor for boards abuts the back of the wall. Since the plasterboard is formed by hardening plaster and covering it with paper, as shown in FIG. 8, the leg portion of the anchor may tear the paper on the back of the wall and sink into the plasterboard. Thus, due to breakage of the plasterboard, the article mounted may loosen or become shaky.
An object of the present invention is to provide an anchor for boards which prevents loosening and shaking, which will not break plasterboards, and which is easy to manufacture.
According to the present invention, there is provided an anchor for boards, comprising a socket including a tubular portion, a plurality of split pieces integral with the tubular portion and having intermediate portions slightly bent outwardly, the socket being integrally provided with a flange at one end thereof and a nut member at the other end thereof, and a screw inserted into the socket and threaded into the nut member, wherein the split pieces have their outer peripheral surfaces covered with a resilient member.
According to the present invention, the socket is inserted into the resilient member and the resilient member is made to contact with the socket.
According to the present invention, the resilient member is formed with as many slits as the split pieces so that portions of the resilient member disposed between the slits align with the split pieces.
The resilient member may be made of a heat-shrinkable resin.
From another aspect of the invention, there is provided a method of manufacturing the anchor for boards, comprising the steps of: providing a socket including a tubular portion, a plurality of split pieces integral with the tubular portion and having intermediate portions slightly bent outwardly, the socket being integrally provided with a flange at one end thereof and a nut member at the other end thereof; inserting a screw into the socket and threading the screw into the nut member; cutting the resilient member to a suitable length beforehand, inserting the socket into the resilient member so that the split pieces will be covered by the resilient member; and heating the resilient member to heat-shrink the resilient member onto the split pieces to cover outer peripheral surfaces of the split pieces.
From another aspect of the invention, there is provided a method of manufacturing the anchor for boards, comprising the steps of: providing a socket including a tubular portion, a plurality of split pieces integral with the tubular portion and having intermediate portions slightly bent outwardly, the socket being integrally provided with a flange at one end thereof and a nut member at the other end thereof; inserting a screw into the socket and threading the screw into the nut member; inserting the socket into the resilient member so as to cover the split pieces; cutting the resilient member to a suitable length; and heating the resilient member to heat-shrink the resilient member onto the split pieces to cover outer peripheral surfaces of the split pieces.
With this anchor for boards, since the metallic spread portion having a plurality of split pieces has its outer periphery covered with resin, due to its resilience, the resin acts as a buffer between the plasterboard and the metallic spread portion of the anchor. Thus, the anchor for boards according to the present invention will not damage the plasterboard, and the member to be mounted can be reliably fixed to the wall.
According to the method for manufacturing the anchor for boards, such anchors can be mass-produced easily.